Process for the production of hydrogen

ABSTRACT

A process and apparatus are disclosed for the generation of hydrogen from hydrogen rich compounds. The process uses hydrogen peroxide as an oxidizer with a hydrogen rich compound forming a mixture such that when the mixture is exposed to a catalyst forming a hydrogen rich gas.

CROSS REFERENCE TO RELATED APPLICATION

This application is a Division of copending application Ser. No.10/395,319 filed Mar. 21, 2003, the contents of which are herebyincorporated by reference in its entirety.

FIELD OF THE INVENTION

This invention relates to fuels and processes for the production ofhydrogen. In particular, this invention relates to a fuel mixture, whichwhen used in conjunction with a catalyst generates a hydrogen rich gasthrough autothermal reforming.

BACKGROUND OF THE INVENTION

The production of hydrogen (H₂) is a very important process. It is usedin oil refineries, the production of fine chemicals, and energyapplications. One method of producing hydrogen is the steam reformingprocess, wherein hydrocarbons are catalytically reacted with steam athigh temperature to produce hydrogen and oxides of carbon. This is themost common method of producing hydrogen, or hydrogen and carbon oxidemixtures. Currently, natural gas predominates as a feedstock over otherhydrocarbons, e.g., naphtha, LPG, refinery gases. The catalytic steamreforming process in tubular furnaces was invented by BASF, and was usedin the United States in the early 1930s. The principal purposes were toproduce hydrogen from natural gas for hydrogenation purposes and tosynthesize ammonia. The process was initially carried out at lowpressures (0.4-1 MPa) and temperatures close to 800° C., andsubsequently higher pressures (up to 4 MPa) and temperatures (up to 950°C.) are used today.

A special type of steam reforming is autothermal reforming, and is alsocalled catalytic partial oxidation. This process differs from catalyticsteam reforming in that the heat is supplied by the partial internalcombustion of the feedstock with oxygen or air, and not supplied from anexternal source.

Modification of the process, using air as the oxidizer was developed forammonia synthesis, and recently, oxygen based gasification has beenintroduced into methanol synthesis.

SUMMARY OF THE INVENTION

The present invention is a process for generating hydrogen for use inchemical processes, or for use as a fuel for fuel cells. The inventioncomprises mixing an oxygenate and an oxidizer in the presence of aninitiator. In one embodiment, the oxygenate is selected from alcohols,diols, triols, ethers, ketones, diketones, esters, carbonates,dicarbonates, oxalates, sugars, and mixtures thereof. In anotherembodiment the oxidizer is selected from hydrogen peroxide, organicperoxides, hydroperoxides, and mixtures thereof. In a preferredembodiment, the initiator comprises a catalyst.

In a preferred embodiment, the process comprises flowing a mixture of anoxygenate and hydrogen peroxide over an initiator. The preferredinitiator is a catalyst mixture that comprises a first catalyst fordecomposing the hydrogen peroxide and a second catalyst for catalyticautothermal reforming of the oxygenate.

An aspect of the present invention is an apparatus for generatinghydrogen from a fuel mixture of an oxygenate and an oxidizer. In oneembodiment, the apparatus comprises a housing for holding a catalyst bedand having an inlet for admitting the fuel and an outlet for directing aproduct stream rich in hydrogen gas. In one embodiment the catalyst bedcomprises a mixture of catalysts with a first catalyst for decomposingthe oxidizer and a second catalyst for reforming the oxygenate.

Another aspect of the invention is a liquid fuel for generatinghydrogen. The liquid fuel comprises an organic compound and an oxidizer.In one embodiment the organic compound is an oxygenate and preferably analcohol and the oxidizer is hydrogen peroxide.

Other objects, advantages and applications of the present invention willbecome apparent to those skilled in the art after the following detaileddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of the process for generating a hydrogen rich gas;

FIG. 2 is a graph depicting the mole fractions of hydrogen and oxygen indesired fuel compositions;

FIG. 3 is one embodiment of the apparatus for generating a hydrogen richgas; and

FIG. 4 is an alternate design of the apparatus for generating a hydrogenrich gas.

DETAILED DESCRIPTION OF THE INVENTION

Hydrogen production is important for chemical processes and energyapplications. A combination of catalytic steam reforming and autothermalreforming is an efficient means for converting a hydrocarbon to ahydrogen (H₂) rich gas. A process and fuel that utilizes autothermalreforming and produces hydrogen on demand can be useful for intermittentprocesses.

One use for intermittent hydrogen production is for fuel cells, wherehydrogen is needed for variable demand. An example of the needs forautomotive applications is shown in Table 1. TABLE 1 Alternate fuel forautomotive applications Automotive Applications -Alternate Fuel RequiredRange 300 miles Average Speed 50 mph Average Propulsion Power Needed 14kW Cell to Wheel Efficiency 0.81 Density of Storage Means 0.9 kg/litreH₂ Capacity of Storage Means 7 wt. % H₂ Fuel Cell Performance 1 0.7 VFuel Cell Performance 2 600 mA/cm² Overall Energy Required 373 MeJOverall Hydrogen Required 5.5 kg Mass of Storage Means Required 79 kgVolume of Storage Means Required 88 litres 23 gallons CO₂ EmissionReduction Factor 2.30 Fuel Cost 1.30 $/gallon (20¢/lb H₂O₂; 1.35$/gallon EtOH) Cost per mile to consumer 0.10 $/mile Traditional FuelCost per mile 0.07 $/mile

The present invention is a process and a fuel for generating hydrogen.The process comprises mixing an oxygenate and oxidizer in the presenceof an initiator. It is preferable that the oxygenate and oxidizer areliquids, or that a mixture of the oxygenate and oxidizer form asubstantially liquid mixture at normal environmental temperatures, i.e.,from about −40° C. to about 50° C. or over a portion of this temperaturerange, especially, from about 0° C. to about 40° C. When this mixture isbrought into contact with an initiator, the oxidizer decomposes andgenerates heat, oxygen and water. The mixture may be mixed as themixture is brought into contact with the initiator, or the mixture maybe pre-mixed and subsequently brought into contact with the initiator.The resulting heat and water concurrently causes steam reforming of theoxygenate, according to:

An initiator can be any means for starting the decomposition of theoxidizer, and includes, but is not limited to, heat, a chemicaladditive, and a catalyst. Heat as an initiator can be provided by aheated wire through electrical resistance, or combustion of a portion ofthe fuels. A chemical additive when mixed with the fuel reacts with theoxidizer to generate heat and oxygen can be an appropriate initiator. Anexample of a chemical initiator is potassium permanganate (KMnO₄).Preferably, the initiator can be a catalyst, wherein the catalyst is oneselected to decompose the oxidizer and generate heat and oxygen.

Using thermodynamic data from an HYSYS™, by Hyprotech, Ltd., CalgaryCanada, the reaction of ethanol and hydrogen peroxide showed thereaction was preferred to produce carbon monoxide and hydrogen. Theresults of the reaction are shown in Table 2 for the reaction:C₂H₅OH(g)+H₂O₂(g)→2 CO(g)+3 H₂(g)+H₂O(g)  (eqn. 2)

TABLE 2 Thermodynamics of ethanol oxidation with hydrogen peroxide T ΔHΔS ΔG C Kcal Cal/K Kcal K Log(K) 0.000 −22.421 108.483 −52.0534.482E+041 41.652 100.000 −20.837 113.457 −63.174 1.008E+037 37.003200.000 −19.698 116.182 −74.670 3.113E+034 34.493 300.000 −18.941117.644 −86.369 8.637E+032 32.936 400.000 −18.493 118.371 −98.1747.526E+031 31.877 500.000 −18.265 118.689 −110.030 1.274E+031 31.105600.000 −18.187 118.786 −121.905 3.276E+030 30.515 700.000 −18.230118.741 −133.782 1.115E+030 30.047 800.000 −18.375 118.599 −145.6504.617E+029 29.664 900.000 −18.609 118.391 −157.500 2.206E+029 29.3441000.000 −18.922 118.135 −169.326 1.172E+029 29.069 Molecular wt. AmountAmount Volume Formula g/mol Conc. wt-% mol g l or ml C₂H₅OH(g) 46.06957.526 1.000 46.069 22.414 H₂O₂(g) 34.015 42.474 1.000 34.015 22.414g/mol wt-% mol g l or ml CO(g) 28.010 69.953 2.000 56.021 44.827 H₂(g)2.016 7.551 3.000 6.047 67.241 H₂O(g) 18.015 22.496 1.000 18.015 22.414

This indicates a significant energy release in the production ofhydrogen when using hydrogen peroxide as an oxidizer. Experiments wereconducted in lab scale quantities to verify that sufficient heat isgenerated to reform a mixture of alcohol and water without addingadditional heat.

EXAMPLE 1

Pure ethanol was mixed with 30% aqueous hydrogen peroxide underatmospheric conditions. The mixture was oxidized using the catalystMnO₂. The test consisted of mixing 2 gm of pure ethanol with 2 gm of 30%hydrogen peroxide. The reaction was very exothermic, and a large amountof gas was produced. The gas product composition comprised about 30volume percent of H₂, about 22 volume percent of CO₂, and a small amountof CO; and the liquid product composition included ethoxy-acetic acid,and 2-propanol based on gas chromatography-mass spectroscopy (GC-MS).

The process is as shown in FIG. 1. A fuel comprising, for example, amixture of ethanol and hydrogen peroxide enters a reactor 10 through aninlet port 12. Reactor 10 comprises a catalyst bed holding adecomposition catalyst for decomposing the hydrogen peroxide. Theoperating conditions are at ambient pressure and at a temperature fromabout −20° C. to about 50° C. The decomposition reaction decomposes thehydrogen peroxide and generates heat and a first product stream 14,including water and oxygen. The product streams 14 is directed to asecond reactor 20 comprising a second catalyst bed holding a reformingcatalyst. The reforming catalyst is chosen to reform the ethanol andwater to form a second product stream 22, which includes a gascomprising hydrogen, carbon dioxide, and carbon monoxide. The reformingreaction is endothermic and requires the addition of heat. The heat fromthe decomposition reaction is transferred to the second catalyst bed viaan appropriate heat transfer means 26. The second reactor 20 is operatedat ambient pressure and at a temperature between about 200° C. and about1100° C.

Optionally, the second product stream 22 is directed to a third reactor30 comprising a third catalyst bed. The third catalyst bed holds a watergas shift (WGS) catalyst for performing the water gas shift reaction.The WGS reactor is operated at ambient pressure and at temperaturesbetween about 180° C. and about 300° C. This produces additionalhydrogen while converting carbon monoxide to carbon dioxide in a thirdproduct stream 32.

The process also provides for optional preheating of the fuel to thedecomposition catalyst with a heat exchanger 34 when excess heat isgenerated in the process.

The process requires an oxidizer that is a compound that gives up itsoxygen readily, and generates heat in the process of giving up itsoxygen for further chemical reaction. Oxidizers include, but are notlimited to, hydrogen peroxide, organic peroxides, hydroperoxides, andmixtures thereof. Preferably, the oxidizer is a liquid, or is readilysoluble in a liquid to form a liquid phase at normal environmentalconditions. A preferred oxidizer is hydrogen peroxide, or hydrogenperoxide in water. When the hydrogen peroxide is in water, it ispreferred that the aqueous hydrogen peroxide concentration be less than90 weight percent, with a more preferred hydrogen peroxide concentrationof less than 50 weight percent.

The determination of an appropriate mixture for the fuel includeswhether there is adequate hydrogen and adequate oxygen in the mixture.However, an initial look at possible fuel mixtures can be analyzed froman overall composition. Specifically, looking at the ratios of hydrogen(H), oxygen (O), and carbon (C). One method is by graphing the positionsof fuel compositions on a triangular graph showing the overallcompositions of H, O and C. Components of potential fuels and fuels arelisted in Table 3 and plotted on FIG. 2 in atomic ratios. Fuel or FuelApproximate Atomic Ratio of Compound H C O Graph Symbol Biomas 2 1 1 BEthanol 3 1 0.5 E Methanol 4 1 1 M Glycol 3 1 1 G Fuel 1 5 1 2 F1 Fuel 28 1 3 F2 Fuel 3 6 1 3 F3 Fuel 4 7 1 3 F4

Aspects of the compositions are that for increasing oxygen (O) content,activation is lower and therefore reforming temperature is lower; andfor increasing hydrogen (H) content more H₂ is generated from reforming.

From FIG. 2, a preferred atomic concentration of hydrogen in the mixtureof organic compound and oxidizer is in the range of 0.5 atomic fractionto about 0.8 atomic fraction with a more preferred range from about 0.6atomic fraction to about 0.68 atomic fraction; and a preferred atomicconcentration of oxygen in the mixture is from about 0.1 atomic fractionto about 0.5 atomic fraction with a more preferred concentration fromabout 0.15 atomic fraction to about 0.35 atomic fraction.

The process requires an organic compound. An organic compound of choiceis an oxygenate, that is, a hydrocarbon compound that has been alteredwith the addition of at least one oxygen atom to the hydrocarboncompound. Oxygenates include, but are not limited to, alcohols, diols,triols, ethers, ketones, diketones, esters, carbonates, dicarbonates,oxalates, organic acids, sugars, and mixtures thereof. The oxygenates ofchoice will be compounds that are generally in a liquid state at normalenvironmental conditions, or are soluble in a liquid to form a liquidsolution at normal environmental conditions. Suitable oxygenatesinclude, but are not limited to, alcohols having 12 or fewer carbons,ketones having 12 or fewer carbons, esters having 12 or fewer carbons,diols having 12 or fewer carbons, triols having 12 or fewer carbons,ethers having 12 or fewer carbons, carbonates having 12 or fewercarbons, dicarbonates having 12 or fewer carbons, oxalates having 12 orfewer carbons, organic acids having 12 or fewer carbons, sugars having12 carbons or less, and mixtures thereof.

Preferably, the oxygenates are alcohols, including diols and triols,having 8 or less carbons, and ethers having 8 or less carbons. Examplesof preferred oxygenates are methanol and ethanol. Other oxygenates thatare preferred include propanols, butanols, amyl alcohols, hexanols,dimethyl ether, isopropylether, dimethoxymethane, and sorbitols.

The oxygenate and oxidizer are mixed in the presence of an initiator togenerate a hydrogen rich gas. Preferably the initiator is a catalyst.The catalyst can comprise one or more metals selected from calcium (Ca),scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese(Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn),strontium (Sr), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum(Mo), technetium (Tc), ruthenium (Ru), rhodium (Rh), palladium (Pd),silver (Ag), cadmium (Cd), barium (Ba), lanthanum (La), hafnium (Hf),tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir),platinum (Pt), gold (Au), and mercury (Hg). The catalyst can includeoxides of the metal, sulfides and other sulfur compounds of the metaland sols comprising the metal. Preferred catalysts comprise one or moremetals from vanadium, iron, cobalt, ruthenium, copper, nickel,manganese, molybdenum, platinum, gold, silver, palladium, rhodium,rhenium, osmium, and iridium, with the more preferred catalystcomprising iron, cobalt, nickel and manganese.

The catalyst can be deposited on a support for increasing the surfacearea of the catalyst when reacting the mixture of oxygenate andoxidizer. Materials suitable for supports include, but are not limitedto, inorganic oxides such as silicas, aluminas, titania, zirconia,yttria, and molecular sieves. Other supports include, but are notlimited to, carbon, silicon carbide, diatomaceous earth, and clays.

When mixing the oxygenate and oxidizer, there must be sufficientoxidizer to generate heat sufficient to heat the mixture to a reformingtemperature, and there must be sufficient oxygenate to be reformed andgenerate a hydrogen rich gas having at least 2 weight percent hydrogenas hydrogen gas (H₂), and preferably at least 5 weight percent, and morepreferably at least 7 weight percent. In order to achieve this hydrogenconcentration, the mass ratio of oxygenate to oxidizer needs to bebetween about 0.25 and about 9.75. Preferably, the mass ratio is betweenabout 0.7 and about 3.

The process autothermally reforms the oxygenate with water and heat fromthe decomposition of the oxidizer, and in the presence of a catalystgenerates a gas that is rich in hydrogen, i.e. a gas having at least 5weight percent hydrogen (H₂). When the oxidizer is hydrogen peroxide,the reaction is very vigorous, and the reaction can be lessened with amoderator or diluent. An appropriate diluent is water, wherein the wateris at least partially consumed in the reforming of the oxidizer, asshown in equation 1. The water can be added separately, or be mixed inwith the oxidizer by using an aqueous solution of hydrogen peroxide. Byusing an aqueous solution of hydrogen peroxide, the process uses anoxidizer that is cheaper and easier to produce.

The process can comprise multiple catalysts. A first, or decompositioncatalyst can be used for the decomposition of the oxidizer and a second,or reforming catalyst can be used for the autothermal reforming of theoxygenate. The process comprises flowing a mixture of oxygenate andoxidizer over the first catalyst, wherein the first catalystexothermally decomposes the oxidizer to heat the mixture. The resultingmixture comprises the oxygenate and oxygen, and can also include steamgenerated from the decomposition of the oxidizer. The mixturesubsequently flows over a second catalyst, wherein the heated mixtureundergoes reformation to generate a hydrogen rich gas.

The first catalyst for decomposition of the oxidizer is preferably acatalyst comprising at least one metal selected from vanadium, iron,cobalt, ruthenium, copper, nickel, manganese, molybdenum, platinum,gold, silver, palladium, rhenium, rhodium, osmium, and iridium. Thecompound can be an oxide, sulfide, or other compound of the metal. Amore preferred compound is manganese oxide (MnO₂).

The second catalyst for reforming the oxygenate is preferably a catalystcomprising at least one metal selected from chromium, gold, zinc,copper, platinum, silver, palladium, rhodium, rhenium, osmium,ruthenium, and iridium. The compound can be an oxide, sulfide, or othercompound of the metal, with a more preferred compound comprising zincoxide (ZnO).

The process comprises using the heat generated by the decomposition ofthe oxidizer to heat the oxygenate, water, and oxygen to facilitatereforming the oxygenate over a catalyst. The process may comprise theuse of separate catalyst beds with a first catalyst bed holding thedecomposition catalyst for the decomposition step, and a second catalystbed for the reformation step. One embodiment using separate catalystbeds comprises flowing the mixture in a countercurrent method, whereinthe mixture of oxygenate and oxidizer first flows over the firstcatalyst bed, and then reversed direction to flow over a second catalystbed in thermal communication with the first catalyst bed. The catalystbeds may be disposed in an apparatus comprising an inner tube holdingthe second catalyst bed, and an outer tube holding the first catalystbed and surrounding the inner tube.

In an alternative embodiment, the process flows the oxygenate andoxidizer concurrently over the first and second catalysts. Thedecomposition and reforming catalysts can be commingled in a singlecatalyst bed, where the catalysts are heated with the decomposition, andreformation occurs in the presence of the heated mixture, generating areformate gas.

Optionally, the process includes a water-gas shift processing step. Thewater-gas shift processing step comprises flowing the reformate gas overa third catalyst in the presence of steam at an elevated temperature.The carbon monoxide and steam react to form hydrogen and carbon dioxide,as shown in equation 3.

The third, or watergas shift catalyst comprises at least one metalselected from iron, cobalt, nickel, copper, zinc, yttrium, zirconium,niobium, molybdenum, technetium, ruthenium, rhodium, palladium, silver,cadmium, lanthanum, hafnium, tantalum, tungsten, rhenium, osmium,iridium, platinum, gold, and mercury. Preferably, the watergas shift isdeposited on a support. Supports include inorganic oxides listed above,and the process for depositing a catalyst metal on a support are knownto one skilled in the art.

The process may optionally include an oxidation step for the selectiveoxidation of carbon monoxide in the reformate gas stream to carbondioxide. The oxidation step comprises flowing the hydrogen richreformate gas over a fourth catalyst, wherein the fourth catalystcomprises at least one metal selected from ruthenium, platinum, gold,and palladium.

An aspect of the present invention is an apparatus for performing theprocess. The apparatus includes a housing for holding catalyst beds forthe fuel to flow over. The housing has an inlet for admitting afeedstream, where the feedstream is a fuel comprising a mixture of atleast one organic compound and at least one oxidizer. The apparatusincludes a first catalyst bed having an inlet in fluid communicationwith the housing inlet, and an outlet for a first product stream. Thefirst catalyst bed comprises a decomposition catalyst for decomposingthe oxidizer and is as described above. The apparatus further includes asecond catalyst bed having an inlet in fluid communication with thefirst catalyst bed outlet, and an outlet for a second product stream.The second catalyst bed comprises a reforming catalyst for reformulatingthe fuel and is as described above.

In one embodiment, the apparatus further comprises a third catalyst bed.The third catalyst bed includes a catalyst for performing the water gasshift reaction:

Suitable catalysts for the water gas shift reaction comprise at leastone metal selected from iron, cobalt, nickel, copper, zinc, yttrium,zirconium, niobium, molybdenum, technetium, ruthenium, rhodium,palladium silver, cadmium, lanthanum, hafnium, tantalum, tungsten,rhenium, osmium, iridium, platinum, gold, and mercury. Preferably thecatalyst comprises at least one metal selected from cobalt, iron,ruthenium, copper, and nickel. A preferred catalyst for the water gasshift reaction includes copper (Cu) and zinc oxide (ZnO)

One embodiment of the present invention is an apparatus as shown in FIG.3. The apparatus comprises a housing 40 having a cylindricalconfiguration. Inside the housing 40 a first catalyst bed 42 is disposedhaving a generally toroidal configuration. The fuel enters an inlet port44 flows over the first catalyst bed 42, and exits a first bed outletport 46. The first bed outlet port 46 in fluid communication with asecond catalyst bed inlet port 48. The product stream from the firstcatalyst bed 42 flows over a second catalyst bed 50 and exits a secondcatalyst bed outlet port 52. The heat generated in the first catalystbed 42 provides a heat source to the second catalyst bed 52 which isabsorbed due to the endothermic reaction of the reforming reaction inthe second catalyst bed 50.

An alternate embodiment of the apparatus includes a third catalyst bed54 as shown in FIG. 4. The third catalyst bed comprises a catalyst forperforming the water gas shift reaction, wherein the second catalystoutlet port 52 is in fluid communication with the third catalyst bedinlet port 56. The product stream flows over the catalyst bed 54 andexits the third catalyst bed outlet port 58 with a hydrogen rich gasstream.

The invention is intended to include alternate configurations, includinglayering of the catalyst beds with fluid flow traversing back and forththrough alternating beds. It is also intended to include, as analternate embodiment, a commingling of the first and second catalystbeds to provide concurrent decomposition of the oxidizer and reformationof the alcohol, or other oxygenate.

Optional features that may be included in the design include heatconducting fins within the catalyst bed to facilitate heat transfer fromone catalyst bed to another.

In an alternate embodiment, the present invention includes a housing forholding a catalyst bed, and having an inlet for admitting a feedstreamand an outlet for delivering a product stream. The catalyst bedcomprises a catalyst that is a mixture of catalysts for combining theprocess of decomposing the oxidizer and reformulating the organiccompound using the energy generated by the decomposition of the oxidizerto drive the reformulation reaction.

Fuels are typically composed of a substantially pure component, or amixture of components comprising individual constituents wherein eachconstituent can be a fuel, and wherein when the fuel is mixed with anoxidizing agent combustion occurs. Oxidizer and fuel are generally keptseparate usually because the oxidizer is cheap, such as air, and doesnot need to be stored, and can be mixed with the fuel as needed. Forexample, in the case of the automobile internal combustion engine, theoxidizer (air) is mixed in a carburetor or in the fuel injector. Othercircumstances that necessitate separation of oxidizer and fuel includeshypergolic fuels that combust upon contact with the oxidizer. A featureof the present invention is that the fuel and oxidizer are mixed for theproduction of H₂ and not for combustion and optionally the fuel andoxidizer are premixed and from a stable mixture.

Increasingly, specialized fuels are needed for specialized functions. Animportant aspect of a fuel is its ability to be readily stored andtransported. For example, a fuel in a liquid form at standardenvironmental temperatures (−40° C. to 50° C.) is easily transported andstored. This provides for convenience of use with the delivery of thefuel to an appropriate device for using the fuel, such as an engine. Afuel that can be used to generate hydrogen as a single mixture providesconsiderable convenience for many purposes, such as, for example,supplemental hydrogen for petrochemical processes, hydrogen for PEM fuelcells, etc. It is preferred that the fuel be a pre-mixed compositionhaving the necessary composition such that when passed over a catalystgenerates a hydrogen rich gas. Preferably, the fuel is in a liquid statein the temperature range over which the fuel is normally exposed, and iscomprised of chemicals having a relatively low toxicity.

Such a fuel, for use in hydrogen production instead of combustion,wherein the hydrogen is then consumed to generate power, is one that isa mixture of a organic compound and an oxidizer. The term fuel usedhereinafter refers to a mixture of an organic compound and an oxidizer.A fuel suitable for the generation of hydrogen, when the fuel is mixedwith an initiator, has an oxygenate concentration of at least 20 weightpercent, and an oxidizer with a concentration of at least 15 weightpercent. The fuel has hydrogen that is readily produced uponreformation, and has a hydrogen concentration of at least 5 weightpercent. Preferably, the hydrogen concentration in the fuel is at least7 weight percent, and more preferably at least 9 weight percent. Inaddition, the fuel has oxygen in the mixture with a concentration of atleast 20 weight percent. Preferably, the oxygen concentration is greaterthan 40 weight percent, and more preferably greater than 50 weightpercent.

In one preferred embodiment, the organic compound comprises anoxygenate. Suitable oxygenates are compounds that have a substantiallyliquid phase at normal environmental conditions, or are substantiallysoluble in an appropriate liquid at normal environmental conditions.Normal environmental conditions would be typically from about 0° C. toabout 40° C., but could include temperatures as low as −40° C. and ashigh as about 65° C. Suitable oxygenates include, but are not limitedto, alcohols, diols, triols, ethers, ketones, diketones, esters,carbonates, dicarbonates, oxalates, and carbohydrates such as sugars.Preferably, the oxygenates are selected from cheap chemicals such asmethanol, ethanol, propanols and butanols. The oxygenates may alsoinclude mixtures of oxygenates. The oxygenate has a concentration fromabout 20 weight percent to about 91 weight percent of the fuel.

The fuel also comprises an oxidizer. Suitable oxidizers are eithersubstantially liquid at normal environmental conditions, or remains in asubstantially liquid phase when mixed with an appropriate liquid, suchas an oxygenate, or water. Oxidizers that are suitable include, but arenot limited to, hydrogen peroxide, organic peroxides, andhydroperoxides, with a preferred oxidizer being hydrogen peroxide. Theoxidizer in the fuel has a concentration from about 20 weight percent toabout 90 weight percent.

The oxygenate and oxidizer are mixed in a mass ratio from about 0.25 toabout 9.8, and preferably from about 0.45 to about 4.0.

Optionally, the fuel includes a diluent, wherein the diluent is acompound that provides stability to the fuel when stored, andcontributes to the production of hydrogen from the fuel when the fuel isprocessed to generate a hydrogen rich gas. A suitable diluent is water.Water provides stability to the mixture, as well as a source of hydrogenduring a water-gas shift reaction.

The fuel may be further blended with appropriate organic compounds forcontrolling mixture properties, such as for example lowering mixturefreezing points or raising mixture boiling points.

When the oxygenate comprises a solid, it is desirable that the oxygenatebe soluble in the diluent or oxidizer so as to form a liquid solution.An example would be a sugar in a water and hydrogen peroxide solution.

As an example, ethanol was used as the preferred oxygenate, hydrogenperoxide as the oxidizer, and water as the diluent, computations wereperformed for determining the amount of hydrogen (H₂) produced. Table 4lists the amount of hydrogen for varying composition of the threecomponents. TABLE 4 Mass Fraction of Hydrogen Produced Mass Flow Ratelb/hr Mass Fraction H₂ Produced Water Ethanol Hydrogen Peroxide WithoutEnergy With Energy lb./hr. lb./hr. lb./hr. Recycle Recycle 10 40 330.0910 0.0954 10 40 34 0.0925 0.0956 10 40 35 0.0935 0.0945 10 40 360.0932 0.0933 10 40 37 0.0920 0.0920 15 25 22 0.0748 0.0751 15 25 230.0779 0.0797 15 25 24 0.0790 0.0795 15 25 25 0.0774 0.0774 15 25 260.0754 0.0754 23 5 10 0.0125 — 23 6 10 0.0130 — 23 7 10 0.0131 — 23 8 100.0131 — 23 9 10 0.0129 —

The results show that a diluent content can be substantial, and with adiluent content as high as 24 weight percent, a gas having at least 7weight percent H₂ can be generated. The diluent has a concentration ofless than about 40 weight percent. The amount of diluent will depend onthe choice and relative ratios of oxygenate and oxidizer. The diluentcan provide water for the reformation reaction, added stability to thefuel mixture, or other enhancements of selected physical properties,such as, for example, a fuel's boiling point.

In addition the diluent helps bring the fuel mixture to a value in amore stable range. Preferably, the concentration of oxygenate is in therange from about 30 weight percent to about 70 weight percent, and theoxidizer has a concentration in the range from about 30 weight percentto about 70 weight percent.

In an alternate embodiment, the organic compound comprises ahydrocarbon. The hydrocarbons are preferably paraffins. Suitablehydrocarbons include, but are not limited to methane, ethane, propanes,butanes, pentanes, hexanes, heptanes, octanes, nonanes, decanes,dodecanes, and mixtures thereof.

Preferably, the hydrocarbons have a substantially liquid phase, or aresubstantially soluble in a liquid phase at normal environmentalconditions.

A comparison of hydrogen production of various organic compounds withhydrogen peroxide as the oxidizer water as a diluent are listed inTables 5 and 6. In addition to hydrocarbons, and alcohols, othercompounds are possible, including sugars (glucose) dissolved in asolution of water and hydrogen peroxide. TABLE 5 Comparison of organiccompounds properties. Steam reformability at 90% conversion Temper- L orV + Toxicity H Content ature Mole Ratio Contact Time Pressure to LD50(mg/kg) LC50 (mg/liter) Formula wt. % ° C. water:fuel or GHSV CatalystLiquify (psi) Oral-Rat Inhalation-Rat Methanol CH₃OH 12.58 280 1.8:1 300 msec Unavailable L 5628 Ethanol C₂H₅OH 13.13 615 13:1 5000/hour V₂O₅L 7060 Isopropanol C₃H₇OH 13.42 L 5045 Butanol C₄H₉OH 13.60 L 790Methane CH₄ 25.13 790 1.1:1  27600/hour  NiO—CaO V, >10000 >5 EthaneC₂H₆ 20.11 V, 610.9 Propane C₃H₈ 18.29 600  3:1 1000/hour Pt—Sn V, 139.0Butane C₄H₁₀ 17.34 660  3:1  10 msec Unavailable V, 35.2 658 for 4 hoursPentane C₅H₁₂ 16.76 L >2000 Hexane C₆H₁₄ 16.37 L 28710 Dodecane C₁₂H₂₆15.38 L Dimethylether C₂H₆O 13.13 L Isopropylether C₆H₁₄O 13.81 L 8470Dimethoxymethane C₃H₈O₂ 10.60 L Glucose C₆H₁₂O₆ 6.71 630 93:1 30 secUnavailable L 25800 Sorbitol C₆H₁₄O₆ 7.75 L 15900

TABLE 6 Comparison of organic compounds H₂ content of gas produced. HContent Mass Flow Rate lb/hr H Content after Temperature Fuel Formulawt. % Renewable Water H₂O₂ Fuel reaction (wt %) ° C. Conversion MethanolCH₃OH 12.58 Y/N 0.0 1.0 2.15 10.11 339.7 98.7 Ethanol C₂H₅OH 13.13 Y 0.01.0 1.16 9.66 645.5 99.7 Isopropanol C₃H₇OH 13.42 N 0.02 1.0 0.94 9.46704.1 99.7 Butanol C₄H₉OH 13.60 N 0.02 1.0 0.88 9.46 705.6 99.8 MethaneCH₄ 25.13 Y/N 0.02 1.0 0.47 10.80 1289.5 97.7 Ethane C₂H₆ 20.11 N 0.021.0 0.55 10.81 1047.4 99.7 Propane C₃H₈ 18.29 N 0.02 1.0 0.58 10.39961.7 99.9 Butane C₄H₁₀ 17.34 N 0.02 1.0 0.60 10.12 902.3 99.6 PentaneC₅H₁₂ 16.76 N 0.02 1.0 0.61 9.97 879.0 99.7 Hexane C₆H₁₄ 16.37 N 0.021.0 0.60 9.79 856.0 99.8 Dodecane C₁₂H₂₆ 15.38 N 0.02 1.0 0.61 9.49829.7 100.0 Dimethylether C₂H₆O 13.13 N 0.02 1.0 1.66 10.37 465.8 99.6Isopropylether C₆H₁₄O 13.81 N 0.02 1.0 0.82 9.44 697.0 99.8Dimethoxymethane C₃H₈O₂ 10.60 Y/N — — — — — — Glucose C₆H₁₂O₆ 6.71 Y — —— — — — Sorbitol C₆H₁₄O₆ 7.75 Y 0.02 1.0 2.31 7.08 267.0 100.0

1. A fuel suitable for the generation of a gas comprising at least 5weight percent hydrogen comprising: an oxygenate wherein the oxygenateconcentration is greater than 20 weight percent; and an oxidizer whereinthe oxidizer concentration is greater than 15 weight percent.
 2. Thefuel of claim 1 further comprising a diluent wherein the diluentconcentration is greater than 2 weight percent of the fuel.
 3. The fuelof claim 2 wherein the diluent has a concentration of at least 25 weightpercent.
 4. The fuel of claim 1 wherein the oxygen concentration is atleast 33 weight percent.
 5. The fuel of claim 1 wherein the oxygenateconcentration is between about 30 weight percent and about 70 weightpercent.
 6. The fuel of claim 1 wherein the oxidizer concentration isbetween about 30 weight percent and about 70 weight percent.
 7. The fuelof claim 1 wherein the oxygenate is selected from the group consistingof alcohols, diols, triols, ethers, ketones, diketones, esters, sugars,and mixtures thereof.
 8. The fuel of claim 7 wherein the oxygenate isselected from the group consisting of methanol, ethanol, n-propanol,isopropanol, 1-butanol, 2-butanol, tert-butanol, 1-pentanol, 2-pentanol,3-pentanol, tert-amyl alcohol, 1-hexanol, 2-hexanol, 3-hexanol,dimethylether, diethylether, isopropylether, methyl tert-butyl ether,methyl tert-amyl ether, glucose, sorbitol and mixtures thereof.
 9. Thefuel of claim 1 wherein the oxidizer is selected from the groupconsisting of hydrogen peroxide, organic peroxides, hydroperoxides, andmixtures thereof.
 10. The fuel of claim 9 wherein the oxidizer ishydrogen peroxide.